\documentclass[tikz]{standalone}

\usetikzlibrary{calc}

\begin{document}
\begin{tikzpicture}
  \def\n{12}
  \def\r{1cm}
  \def\r{0.5in}
  \def\thing#1#2{
    \foreach \i in {0,...,\n} {
      \begin{scope}[shift={({\i * 2 * \r}, 0)}]
        \def\zero{0}
        \fill[white] (0, 0) circle (\r);
        \ifx\i\zero\relax\else
          \fill[#2] (0, 0) -- (0, \r) arc (90:{90 - 360 * \i / \n}:\r) -- (0, 0);
          \draw[#1]    (0, 0) -- (0, \r) arc (90:{90 - 360 * \i / \n}:\r) -- (0, 0);
        \fi
        \draw[#1] (0, 0) circle (\r);
      \end{scope}
    }}
  \thing{gray}{gray!60}
  \begin{scope}[shift={(0, {-2*\r})}]
    \thing{red!60!black}{red!90}
  \end{scope}
\end{tikzpicture}
\end{document}
